Extra-Hard ASTM B628 Silver-Copper Eutectic Alloy
Extra-hard ASTM B628 is ASTM B628 Ag-Cu in the extra-hard temper. The graph bars on the material properties cards below compare extra-hard ASTM B628 to: precious metal electrical contact alloys (top), all alloys in the same category (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
83 GPa 12 x 106 psi
Elongation at Break
1.1 %
Poisson's Ratio
0.36
Shear Modulus
31 GPa 4.4 x 106 psi
Shear Strength
340 MPa 49 x 103 psi
Tensile Strength: Ultimate (UTS)
590 MPa 86 x 103 psi
Thermal Properties
Latent Heat of Fusion
140 J/g
Melting Completion (Liquidus)
780 °C 1430 °F
Melting Onset (Solidus)
780 °C 1430 °F
Specific Heat Capacity
280 J/kg-K 0.066 BTU/lb-°F
Thermal Expansion
19 µm/m-K
Other Material Properties
Density
10 g/cm3 630 lb/ft3
Electrical Conductivity: Equal Volume
84 % IACS
Electrical Conductivity: Equal Weight (Specific)
75 % IACS
Common Calculations
Stiffness to Weight: Axial
4.6 points
Stiffness to Weight: Bending
14 points
Strength to Weight: Axial
16 points
Strength to Weight: Bending
16 points
Thermal Shock Resistance
27 points
Alloy Composition
| Ag | 71 to 73 | |
| Cu | 26.6 to 29 | |
| Zn | 0 to 0.060 | |
| Fe | 0 to 0.050 | |
| Cd | 0 to 0.050 | |
| P | 0 to 0.030 | |
| Pb | 0 to 0.030 | |
| Ni | 0 to 0.010 | |
| Al | 0 to 0.0050 | |
| res. | 0 to 0.21 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Further Reading
ASTM B628: Standard Specification for Silver-Copper Eutectic Electrical Contact Alloy
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015